Interpretive Summary: o determine whether a botanical material has been adulterated (i.e., whether it is authentic), it is necessary to compare the material in question to a series of authentic materials. This is usually done on a global basis by comparing the complete chromatogram or spectrum of the material in question to a family of chromatograms or spectra of the authentic materials. The comparison is made using chemometrics (pattern recognition software). In this study we examined 18 commercial Ginkgo biloba samples and 3 G. biloba reference standards (SRMs 3246, 3247, and 3248) from the National Institute of Standards and Technology. It was determined that 6 of the commercial standards were adulterated by the addition of extra quercetin or quercetin rutinoside. The data show that the determination can be made from routine chromatograms, based either on just the largest peaks or on the whole chromatographic image, or from the UV spectra of a simple water-methanol extraction. Detection of the adulterated samples by analysis of the solid samples by near infra-red analysis was not possible due to the different binders used by different manufacturers. Extraction removed the binder and made the analysis possible.

Technical Abstract:
The fingerprints of 18 commercially available Ginkgo biloba supplements, 12 samples of raw Ginkgo biloba leaves, and 3 Ginkgo biloba Standard Reference Materials from the National Institute of Standards and Technology were acquired directly (no chromatography) by ultraviolet (UV) spectrophotometry and after separation using high performance liquid chromatography with diode array detection. The fingerprints consisted of the UV spectral images, the chromatographic images, and the areas of the21 most prominent chromatographic peaks. Data were analyzed by principal component analysis and SIMCA (soft independent modeling of class analogy). It was determined that 3 of the commercial products were adulterated with rutin, 4 were adulterated with quercetin, and 1 was adulterated with an unidentified flavonol glycoside. SIMCA of the authentic products allowed the adulterated products to be easily distinguished using Q residuals. Authentic supplements and raw leaf materials were easily distinguished. The finely powdered samples were also analyzed by near-infrared (NIR) spectrometry. The authentic and adulterated products could not be distinguished by NIR because of the excipients.